Blasting cartridge



F. H. ARMSTRONG BLASTING CARTRIDGE June 15, 1937.

Filed Dec. 7, 1934 307% A Mw,

ATTORNEY INVENTOR. @mm/1MM;

BY 7H l Patented June 15, 193'7 UNITED STATES aosasws PATENT OFFICE BLASTING CARTRIDGE Y Illinois n Y Application December 7, 1934, Serial No. 756,511

19 Claims.

This invention relates toblasting cartridges, and more particularly to improvements in a blasting cartridge of the type wherein a high pressure gas is employed `as a blasting medium.

In blasting down material, such as coal in coal mines, the size of the drill hole is, under certain conditions, definitely restricted as to diameter, although the hole depth may be substantially varied to suit different conditions. In

l0 blasting cartridges of the high pressure'gas type designed for use in small drill holes it is diilicult in a single chamber, single discharge orice unit to provide a suflicient volume of high pressure gas to `act eiectively in the breaking down of the 15 coal, the volume of gas being limited by the cartridge diameter and the diameter of the discharge orifice through which the blasting charge discharges.

An object of the present invention is to pro- 20 vide an improved blasting cartridge of the high pressure gas type designed to overcome the diflicultles above outlined. Another object is to provide an improved blasting cartridge of the high pressure gas type having improved means of 25 relatively high capacity for storing the blasting pressure in acontainer unit of relatively small external diameter and having improved discharge release means whereby a relatively large volume of blasting pressure may be effectively 3o applied to the work. Still another object is to provide an improved blasting cartridge of the multiple discharge type for effecting sudden release in a dei'lnite sequence, of a large quantity of blasting pressure. Yet another object is to pro- 35 vide an improved cartridge wherein the total amount of energy available in a cartridge of a given length and diameter is divided among a multiplicity of distinct charges and these charges applied to the work at different points 40 along the length of the drill hole in such a manner that each blasting charge has a denite burden to carry.` Yet another object is to provide in a cartridge of the above character a discharge orice at the longitudinal center of the 45 cartridge and another discharge orifice at the inner end of the cartridge and to cause the blasting charges to be discharged in a definite sequence, the central orice rst discharging the primary charge and the end orifice thereafter 50 discharging the secondary charge, there being a denite time interval between the periods of discharge of the two charges. A further object is to provide an improved blasting cartridge wherein the amount of energy is divided into separate 55 charges, together with means for discharging the blasting charges sequentially to impart a prolonged breaking elect iirst on the portion of the mine wall between the face and the inner end of the drill hole and thereafter a breaking eiect at the inner side of the mine wall. 'Ihese and other objects and advantages of the invention will, however, hereinafter more fully appear.

In the accompanying drawing there is shown for purposes of illustration one form which the invention may assume in practice.

In this drawing,-

Fig. 1 is a view in longitudinal section of the illustrative form of the improved blasting cartridge. l

Fig. 2 is a diagrammatic view showing the blasting cartridge in blasting position in the mine wall.

In this illustrative construction there is shown a. blasting cartridge of the multiple discharge type designed for use with a high pressure gas as a blasting medium and comprising cylindrical containers I and 2 arranged in end to end relation in longitudinal alinement and having blasting pressure storing chambers 3 and 4, respectively. 'I'hreaded within the outer end of the container I is a terminal cap 5, while threaded within the inner end of the container 2 is a discharge cap YIi and the adjacent ends of the containers have threadedly secured thereto a combined discharge and terminal cap 1 forming a rigid connection between the two container units. The pressure chamber 3 has an axial discharge orice 8 formed in the cap 1 and terminating in a series of radial discharge ports 9 arranged substantially midway between the ends of the cartridge unit. The pressure chamber 4 has an axial discharge orifice I0 formed in the discharge cap 6 and terminating in a series of radial discharge ports I I arranged at the inner end of the cartridge unit. A conical valve I2 seats on the wall of the discharge orice 8 closing the inner end of the pressure chamber 3. while a similar conical valve I3 seats on the end wall of the discharge orice I0 to close the lnner end of the pressure chamber 4; and these valves are controlled by differential mechanisms I4 and I5, respectively. These control mechanisms may assume a form similar to that disclosed in my copending application Ser. No. 718,715 filed March 30, `1934 (see Fig. 12). The differential control mechanism for the discharge valve I2 comprises a plunger I6 contained in the bore of a control chamber I1 formed in the terminal cap 5. Threaded within the body of this plunger is a valve rod I8 extending axially within the pressure chamber 3 and secured at its inner end to the valve I2. Held against the inner face of the plungerrbody by a keeper I9 threaded on the valve rod is a cup leather 20. The valve rod extends through an opening in a metallic plate 2i secured within the end of the container by the terminal cap 5. and this plate carried a hat leather 22 providing a seal about the valve rod periphery and functioning as a check valve to prevent leakage from the control chamber I1 to the pressure chamber 3 but permitting flow of pressure from the chamber 3 to the control chamber at the inner side of the plunger. The valve rod is provided with an axial passage 23 communicating through radial ports 24 with the pressure chamber 3 and through an axial por'.VV 25 in the plunger with the control chamber at the outervside of the plunger. A spring pressed check valve 26 controls the ilow through passage 25, this check valve per-V mitting flow from the control chamber to the pressure chamber 3 but preventing ilow through the passage 25 in the opposite direction. The valve I2 is provided with an axial guide extension 21 which, together with a bore in the cap 1, serves to center and guide the valve I2 with respect to its seat, and the valve and this guide extension are provided with communicating passages 23 and 29 through which gas may flow from the chamber 3 to a control chamber 30 formed in the cap 1, the latter carrying a suitable packing 3I for sealing the guide extension to prevent leakage from the control chamber 30 to the discharge orifice 3. Reciprocable in the bore oi the control chamber 30 is a plunger 32. identical to the plunger I6, of the differential control mechanism I5 for the valve I3. Threaded within the body of the plunger 32 is a valve rod 33 extending axially within the pressure chamber 4 and connected at its inner end to the valve I3. This valve has an axial guide extension 34, which, together with a bore in the discharge cap 6, serves to center and guide the valve I3 with respect to its seat. The valve rod 33 extends through an opening in a metallic plate 35 held in position within the end of the container 2 by the cap4 1, and this plate carries a hat leather 36 which seals the valve rod and functions as a check valve to prevent leakage of pressure from the control chamber 30 to the pressure chamber 4 while permitting flow of fluid from the chamber 4 to the control chamber 30 at the inner side of the plunger 32. Formed in the valve rod 33 is an axial passage 31 communicating through radial ports 33 with the pressure chamber 4 and through an axial port 39 in the plungerwith the control chamber 30 at the outer side of the plunger. A spring pressed check valve 40 permits ilow of iluid from the control chamber through the axial passage 31 to the pressure chamber 4, but prevents flow through the passage 39 in the opposite direction. Pressure fluid is supplied to the control chamber I1 from any suitable source of high pressure gas through a tubing 4I connected by a nipple 42 to the terminal head 5.

During the blasting operation the cartridge is positioned in a drill hole 43 drilled in the coal face above thc undercut 44 with one series of discharge ports positioned substantially midway between the ends of the hole and the second series of discharge ports positionedat the inner end of the hole. As above pointed out, this arrangement is to divide the total amount of energy available in a cartridge of given length and diameter into a plurality of distinct charges and to apply sequentially these charges to the work at different points along the length of the drill hole in such a manner that each charge has a definite burden to carry. When the cartridge is so positioned, high pressure gas controlled from a remote point is supplied through the tubing 4I to the control chamber I1, through the axial passage 25, past the check valve 26 and through axial passage 23 and ports 24 to the pressure chamber 3. Gas flows from the outer pressure chamber 3 through passages 28, 23, through the control chamber 30 to port 33, past the check valve 40 and through axial passage 31 and ports 33 to the inner pressure chamber 4. The high pressure gas in the control chambers I1 and 30 acting on the outer pressure areas ot the plungers I6 and 32 maintains the discharge valves I2 and i3 tightly against their seats. When a predetermined blasting pressure is attained within the pressure chambers 3 and 4 the supply of high pressure gas to the tubing 4I is cut oil? and the latter is suitably vented to atmosphere thereby reducing the pressure in the control chamber I1. As a result, the pressure in the control chamber I1 at the inner side of the plunger acts on the plunger to move the latter outwardly against the reduced opposing pressure, thereby to effect opening of the valve I2 to release suddenly the blasting charge in the chamber 3 through the discharge orifice B and discharge ports 9. When the pressure in chamber 3 is reduced the pressure within the control chamber 30 is at the same time reduced, and as a result, the pressure in the control chamber 30 at the inner side of the plunger 32 effects movement of the latter outwardly against the opposing reduced pressure to move the control valve I3 oi its seat, and as a result the blasting charge in the chamber 4 is suddenly released through the discharge orifice I0 and discharge ports II.

It will thus be seen that by the particular arrangement of the ports and passages the control valve i2 is iirst released and after a definite time interval the control valve I3 is released so that there is a discharge of blasting pressure from the containers in a definite sequence. The parts are so arranged that the middle series of discharge ports ilrst discharge the primary.

charge and thereafter the inner series of disu charge ports discharge the secondary charge, there being a definite time interval between the periods of discharge of the two charges. Under certain conditions more than two serial discharges may be employed, and in certain instances, the discharge from the several chambers may be substantially simultaneous instead of sequential. These and other uses and advantages cf the improved blasting cartridge will be clearly apparent to those skilled in the art.

While there is in this application specifically described one form which the invention may assume in practice, it will be understood that this form of the same is shown for purposes of illustration and that the invention may be modifled and embodied in various other forms Without departing from its spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is:

1. In a blasting cartridge, a container unit having a plurality of pressure chambers, and means for effecting discharge from said container unit of the blasting charge from one chamber and thereafter automatically effecting discharge from said container unit of the charge from another chamber including means whereby discharge of said first chamber is prerequisite to discharge of said other chamber.

2. In a blasting cartridge, a container unit having a plurality of pressure chambers, a control valve for each pressure chamber for releasing the blasting charge therefrom, and a control mechanism fori each valve including a control chamber and a valve actuating plunger contained in said chamber, the pressure in one of said control chambers being controlled by the pressure in one of said pressure chambers.

3. In a blasting cartridge, a container unit having a pair of serially communicating pressure chambers, means for supplying fluid blasting pressure to said chambers, the pressure being charged to one chamber wholly through the other, and means for serially releasing the blasting pressure from said chambers.

4. In a blasting cartridge, a container unit having a plurality of pressure chambers, means for supplying blasting pressure to said chambers, the pressure being supplied to one chamber through another. and means for releasing the blasting pressure from said chambers in a definite sequence.

5. In a blasting cartridge, a container unit having a plurality of pressure chambers, means for charging blasting pressure in said chambers, the pressure being charged in one chamber through the other, and means lor releasing the blasting pressure from said chambers to the material to be blasted sequentially but rst from the chamber through which pressure is charged to the other.

6. In a blasting cartridge, a container unit having a pair of alined pressure containers each having a pressure chamber, a valve for each chamber for controlling the discharge of blasting pressure therefrom, and controlling means for said valve including for each valve a control chamber, a plunger contained in said control chamber, a valve rod connecting said plunger to its valve and means vfor supplying blasting pressure to said control chamber, the pressure flowing to one pressure chamber through one control chamber and the valve rod and the pressure iiowing from said first pressure chamber to said second pressure chamber through the valve for the first chamber and through the control chamber and valve rod of the other valve.

7. In a blasting cartridge, a container unit adapted to be positioned in a drill hole formed in material to be broken. said container unit consisting of a plurality of connected charge receiving chambers, each having a discharge device, said chambers being proportionate in capacity to the amount of work to be performed at the several points along the length of the drill hole at which said discharge devices will normally be positioned, means for charging said chambers to effect the concurrent presence in each of the same of a fiuid blasting charge at high pl essure, and means for effecting sequential discharge thereof.

8. In a blasting cartridge. a container unit cf relatively great length and relatively small diameter, means dividing said container into two separate chambers adapted to be charged with a compressed fluid, eaelrchamber having a discharge orice, a fluid pressure control valve means for governing said orifice, thus providing the most eicient relation between the volumetric capacity of the chambers and the area of the discharge orifice therefor, means for charging said chambers, and means for sequentially discharging said chambers.

9. In a blasting cartridge, a container unit having a plurality of pressure chambers and means for effecting discharge el the blasting charge from each chamber including a contrcl chamber individual thereto, the control chamber for one pressure chamber connected directly with another pressure chamber.

l0. In a blasting apparatus, a container unit providing a plurality of serially connected chambers, common supply means and independent discharge means for said chambers controllable to effect a sequential charging of said chambers to a blasting pressure and sequential discharge of said chambers to the material to be blasted in the same order.

11. A blasting cartridge comprising a container unit having a plurality of pressure chambers each of which is provided with a discharge oriilce, separate valve means for closing the orifice of each chamber, separate releasable means for holding each valve means in its opening, and means for effecting sequential operation of said separate releasable means.

12. A blasting cartridge comprising a container unit having a plurality of pressure chambers each of which is provided with a discharge orifice, separate valve means for closing the orifice of each chamber, fluid pressure operated separate releasable means for holding each valve means in its opening, and means for effecting sequential operation of said separate releasable means.

13. A blasting cartridge comprising a container unit having a plurality of pressure chambers each of which is provided with a discharge orice, separate valve means for closing the orifice of each chamber, diierential pressure operated separate releasable means for holding each valve means in its opening, and means for eifecting sequential operation of said separate releasable means.

14. A blasting cartridge comprising a container unit having a plurality of pressure chambers each of which is provided with a discharge orice adjacent one end thereof, separate valve means for closing the orifice of each chamber, separate releasable means adjacent the other end of each chamber for holding the valve means of said chamber in its orifice, and means for effecting sequential operation of said separate releasable means.

15. In a blasting cartridge, a container for receivingr a fluid charge at blasting pressure, said container being divided into a plurality of independent compartments, each of which receives its proportionate share of the charge, separate releasing means for each of said plurality of compartments, and means for operating said separate releasing means in a definite sequence.

16. In a blasting cartridge, a container unit having a pair of alined pressure containers each having a pressure chamber, a combined discharge head and control cap for connecting said containers together, a control cap at the outer end of the outer container. a discharge head at the inner end of the inner container, a valve for each container for controlling the discharge of blasting pressure through said discharge heads, and control mechanism for said valves including a control chamber in each of said control caps and a valve actuating plunger reciprocable in each control chamber.

17. In a blasting cartridge, a container unit having a plurality of pressure chambers. and a di'erential valve mechanism for each pressure chamber for controlling the discharge of blasting pressure therefrom and operable to eiect pressure discharge from said chambers in a denite sequence.

18. In a blasting cartridge, a container unit having a plurality of aligned pressure chambers, and blasting pressure operated means operable when a predetermined blasting pressure is simultaneously attained within said chambers for discharging the blasting pressure therefrom in a denite sequence.

19. In a blasting cartridge. a container unit having a plurality of pressure chambers, a discharge orifice for each chamber, the discharge orifice for one chamber arranged between the ends of the container unit, a discharge orifice for another chamber arranged at the inner end of the container unit, and means for etecting the dischargeof blasting pressure from said chambers in a delnite sequence through said discharge orifices.

FRANK H. ARMSTRONG. 

